tion. He didn't want the others to hear what he had to
say. His voice came like a roar from the bottom of a well. "Lieutenant,
do you suppose there's any chance the blast might break up the asteroid?
Maybe split it in two?"

The same thought had occurred to Rip on the _Scorpius_. His calculations
had showed that the metal would do little more than compress, except
where it melted from the terrific heat of the bomb. That would be only
in and around the shaft. He was sure the men at Terra base had figured
it out before they decided that A-bombs would be necessary to throw the
asteroid into a new orbit. He wasn't worried. Cracks in the asteroid
would be dangerous, but he hadn't seen any.

"This rock will take more nuclear blasts than we have," he assured Koa.
He turned his communicator back on and went to the edge of the hole for
a look at Kemp's progress. He was far down now. Pederson was holding one
end of a measuring tape. The other end was fastened to Kemp's shoulder
strap.

The Swedish corporal showed Rip that he had only about eight feet of tape
left. Kemp was almost down. Rip called, "Kemp, when you reach bottom, cut
toward the center. Leave an inverted cone."

"Got it, sir. Be up in two more cuts."

Dominico had connected cable to the bomb terminals and was attaching a
timer to the other end. Without the wooden case, the bomb was like a fat,
oversized can. It had been shipped without a combat casing.

"Koa, make a final check. You can untie the landing boat, except for one
line. We'll be taking off in a few minutes."

"Right, sir." Koa glided toward the landing boat, which was moored out of
sight beyond the horizon.

It was nearly time. Rip had a moment's misgiving. Had his figures or his
sightings been off? His scalp prickled at the thought. But the ship's
computer had done the work, and it was not capable of making a mistake.

Kemp tossed up the last section of thorium and then came out of the hole
himself, carrying his torch.

Rip inspected the hole, saw with satisfaction that it was in almost
perfect alignment, and ordered the bomb placed. He bent over the edge
of the hole and watched Trudeau pay out wire while Dominico pushed the
bomb to the bottom. The Italian made a last-minute check, then called
to Rip. "Ready, sir."

Rip dropped into the hole and inspected the connections himself, then
personally pulled the safety lever. The bomb was armed. When the timer
acted, it would go off.

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